Boiler



Oct. 21, 19 w. H. ARMACOST 2,855,905

' BOILER Filed Nov. 15, 1954 4 Sheets-Sheet 1 g I INVENTOR.

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BOILER Filed Nov. 15, 1954 4 Sheets-Sheet 2 Wilbur H. Armucost [NI E NTOR.

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51 (an A! {W ATTORNEY BOILER Wilbur H. Armacost, Scarsdale, N; Y.,assignor to Combustion Engineering, Inc., New York, N. Y., a corporationof Delaware Application November 15, 1954, Serial No. 468,826

3 Claims. (Cl. 122-478) This invention relates :to high capacity steamgenerators or boilers of the utility type and particularlyto suchboilers wherein steam temperature is controlled by varying the zone ofcombustion longitudinally within the water walled furnace.

The invention, in general, comprises a steam generating unit made up oftwo identical boilers positioned in side by side relation and having acommon steam and water drum as well as a common stack with the unitbeing arranged in a compact and highly efficient manner to provide forefficient operation at a minimum of cost. Each of the boilers is itselfcompact y arranged so as to reduce cost to a minimum and provide aboiler having a low center of gravity as compared with the present dayhigh capacity utility type boilers making the same particularly welladapted for hurricane and earthquake areas. These boilers include anupright elongated furnace having its sole exit for combustion gasesadjacent-the bottom and fired by suitable burners mounted in the ,upperportion of the furnace walls but spaced from .the top thereof andadjustable in such a manner that the zone of combustion may be variedlongitudinally of the furnace. The walls of the furnace as well as .theroof are lined with vertically disposed steam generating tubes withadjacent tubes being welded together throughout their length to form arigid substantially fluid tight wall structure. The steam and water drumof the boilers-is positioned substantially intermediate the upperandlowerends of thefurnacc and is in communication with the inlet andoutlet .of the steam generating tubes in the usual manner with pumpsbeing provided to establish a forced circulation of the boiler waterfrom this drum through the steam generating tubes. Extending from thecombustion gas exit of the furnace is a generally horizontal gas passwhich houses reheater elements and which leads to a vertical gas passextending upwardly therefrom and which houses the superheater elementsof the boiler. Positioned'directly over the horizontal gas pass andintermediate the furnace and the vertical gas pass is the airheater .ofthe boiler which is of such a size relative to the length of thehorizontal gas pass that it occupies substantially the entire spaceintermediate the vertical gas pass and the furnace. Each of the boilersis supported by means of a structural steel framework the uppermostportion of which lies substantially below the upper end of the furnacebut above the center of gravity of the furnace. At this elevation-thefurnace is interconnected with the support structure in such-ama-nnerthat the furnace is suspended therefrom.

It is the object of this invention to provide an efficient andeconomical steam generating unit wherein the boilers are extremelycompact and have alow center of gravity and wherein an increase in thecontrol effect obtained by varying the combustion zone longitudinallywithin the water walled furnace of the boiler is achieved.

"Other and further objects of the invention will become apparent tothose skilled in theart as the description proceeds.

' 2,856,906 Patented on. 21, 1958 With the aforementioned objects inview, the invention comprisesan arrangement, constructionandcombin'a'tion of the elementsofthe boiler in :such a manner as toattain the results desired as hereinafter more particularly set forth inthe following detailed description of an illustrative embodiment, saidembodiment being shown by the accompanying drawing wherein:

Figure 'l is a vertical section of the steam generating unit of thepresent invention taken generally along line 1*1 of Fig. v2 and showingthe two boilers in side by side relation;

'Figure '2 is a vertical section of this generating unit taken alongline 2-4. of Fig. land showing the layout of each boiler;

Figure 3 is a horizontal sectional view of the steam generating unittaken generally along line 3--'3-of Fig. '2;

Figure 4 is a horizontal sectional View through one of the furnaces ofthe steam generating unit at thelocation of the burners, taken generallyalong line 4+4 of Fig. 2, and showing the disposition of the burners inthe furnace;

Figure 5 is a longitudinal sectional view through one of the burnerunits taken generally along line 5--5 of Fig. 4;

Figure 6 is a fragmentary detailed view of the water wall which formsthe inner surface of the furnace;

Figure 7 is a transverse sectional view taken along line 7-7 of Fig. 6.

Referring now to the drawings wherein like reference characters are usedthroughout to designate like elements the steam generating unit depictedtherein comprises two identical boilers 10 and 12' positioned in closelyspaced side. by side relation. Each of these boilers includes anelongated upright furnace 14 tangentially fired by means of burnerunits-16 and having its sole exit for combustion gases, identified as18, located-in the-lower portion thereof. The walls of furnace 14 arelined with vertically extending steam generating tubes 20 which arepositioned in tubes 20 that line the remaining two walls of the furnaceare also interconnected with header 24 which is in turn connected withsteam and water drum 26 through conduits 25, this drum being a commondrum for both boilers of the steam generating unit and being positionedsubstantially midway between the vertical extremities of the furnaces ofthese boilers. Depending from steam and water drum-26are downcomers 28connected to the inlet of pumps 30 which are effective to force boilerwater through conduits 32 and into orifice drum 34 from which it isdistributed to steam generating tubes 20 which have their lower or inletends connected into drum 34.

In order that the flow through each of the tubes 20 will be regulated soas to obtain maximum efficiency each of these tubes is provided at itsinlet with a flow'restrictor (not shown) of preselected size as is wellknown in-the controlled circulation type of boiler. As the boiler wateris forced upward through tubes 20 a portion of this water is convertedto steam with the thus producedsteafm and water mixture entering header24 and then passing;

Extending laterally from furnace exit 18 is horizontal gas pass 36 whichleads. to and is interconnected withupwardly extending gas pass 38Within these gas/passes are positioned the steam heating elements of theboiler with gas pass 36 having reheater 40 disposed therein whichreceives steam through conduit 42 after a portion of its energy has beenutilized and reheats the same to a desired temperature and pressurewhile gas pass 38 has superheater 44 positioned therein andinterconnected with steam and water drum 26 by conduit 46 so as toreceive saturated steam therefrom, which, after passing 1 is positioneda substantial distance below the upper end of furnace 14 and directlyabove horizontal gas pass 36 which is of such a length as to permit theairheater to be snugly positioned between gas pass 38 and furnace 14.

Intermediate the airheaters of the two boilers is a common stack 54which is interconnected with each of the airheaters by means of suitableducts to receive the I,

combustion gases as they pass therethrough and convey these spent gasesto waste.

The entire steam generating unit is supported from a structural steelframework made up of I beams 56 arranged and interconnected in the usualmanner to form a sturdy supporting structure. This supporting frameworkextends only slightly above steam and water drum 26 to an elevationwhich is above the center of gravity of furnace 14 but well below theupper end of the furnace and at which elevation the furnace isinterconnected with the supporting framework in such a manner as to behung therefrom so that the portion of the furnace located below thiselevation expands downwardly while the portion located above thiselevation expands upwardly as the temperature of the water wallsincrease.

The furnace 14 is tangentially fired and for this purpose burner units16 are mounted in the furnace walls at the four corners of the furnace.Fuel, which may be of any desired kind such as pulverized coal, oil, orthe like, is supplied to these burner units through conduits 58 withcombustion supported air being forced through air heater 50 by blower 60and introduced into the burner units from wind box 62 to which it isconveyed by means of duct 64.

Each of the burner units comprises a number of vertically arrangednozzles 66, three such nozzles being shown (Fig. 5), with these nozzlesbeing pivotally mounted around horizontal axes and suitable operatingmechanism such as linkages 68 being provided to control the pivotalmovements of these nozzles and thereby vertically adjust or regulate thedisposition ofthe zone of combustion in the furnace for the purpose ofcontrolling superheat or reheat temperature in a well known manner.

In the boilers of the present invention this type of superheat and/ orreheat control is of increased effectiveness in contrast with that whichhas heretofore been obtained. This increased effectiveness is due toincorporating this type of control in a furnace which has a completelywater cooled roof and is fired adjacent its upper end with the sole exitfor combustion gases being at its lower end. With this novel combinationthe roof tubes, which correspond to the floor tubes in the organizationsheretofore having this control, will remain free of falling ash depositsand other foreign matter and therefore they will have a much higher heatexchange rate than the corresponding floor tubes in prior artorganization which will become coated with this matter which will ofcourse act as a heat insulatorto a great degree.

This effect will of course be most pronounced with pulverized coalfiringwhere ash and foreign matter accumulation will be the greatest and when,employing this fuel the bottom of the furnace of the illustrative organization will be constructed for and provided with means to remove slagtherefrom. When the nozzles 66 are tilted to the extreme position wherethe zone of combustion is at its most remote position from exit 18 thecombustion zone will be located immediately below the roof tubes whichremain clean and in excellent heat absorbing condition. The result ofthis is to substantially increase the heat absorption in the furnaceover that heretofore obtained when the burner nozzles are so tiltedthereby correspondingly further reducing the temperature of the gasesexiting from the furnace and thereby further lowering the steamtemperature. This improved operational elfect is not obtained with priorart organizations which either have the combustion gas exit at the topor do not employ roof tubes with this type of super heat control. Inthese boiler organizations which have the combustion gas exit at theupper end ash and other matter fall to the bottom of the furnace andcollect so as to form a layer over the tubes which line the floorthereby greatly decreasing the heat transfer effectiveness of thesetubes whereby the control effect obtained by tilting the burners to movethe zone of combustion to its most remote position from the furnaceoutlet is substantially impaired.

With the controlled circulation boilers of this invention wherein theentire supporting structure as well as the steam and water drum arelocated a substantial distance below the upper end of the furnace andwhere the gas passes are located relatively close to the ground thecenter of gravity of the entire boiler is extremely low making such aboiler highly desirable in locations where hurricanes and/or earthquakesare prevalent. Moreover this low center of gravity together with theextremely compact arrangement of the boilers and the entire unit resultsin a substantial reduction in cost. By means of the welded water wallconstruction the furnace is extremely rigid enabling it to be suspendedfrom a point intermediate its extremities with a substantial portion ofthe furnace projecting above this point of support without anysubstantial additional support being required for this upwardlyextending portion.

While I have illustrated and described a preferred embodiment of mynovel boiler organization it is to be understood that such is merelyillustrative and not restrictive and that variations and modificationsmay be made therein without departing from the spirit and scope of theinvention. I therefore do not wish to be limited to the precise detailsset forth but desire to avail myself of such changes as fall within thepurview of my invention.

What I claim is:

l. A controlled circulation boiler comprising an upright elongatedfurnace fired in its upper region at a location spaced somewhat belowthe roof of the furnace and having its sole exit for combustion gases atits lower end, a steam generating circuit including longitudinallyextending tubes lining the furnace walls and roof, pump means forestablishing a forced circulation therethrough and a steam and waterdrum supported a substantial distance below' the furnaces upper end,burner means at said location for injecting fuel into said furnace, saidburner means being mounted for pivotal movement about a generallyhorizontal axis, means controllab-ly directing said burner means tovertically adjust the zone of combustion within the furnace to controlwithin limits the temperature of the gases leaving the furnace, agenerally horizontal gas pass extending laterally from said combustiongas exit and having steam heating heat exchange elements disposedtherein operatively connected to receive and heat the steam generated insaid circuit, a support framework for supporting said boiler anddisposed about said furnace, said framework terminating at a heightadjacent said drum and substantially below the upper end of said furnaceand being effective to directly support said drum, said supportframework being interconnected with the furnace walls at said height andin a manner so that the furnace is suspended therefrom.

2. A controlled circulation boiler comprising an upright elongatedfurnace fired in its upper region at a location spaced somewhat belowthe roof of the furnace and having its sole exit for combustion gases atits lower end, a steam generating circuit including longitudinallyextending tubes lining the furnace walls and roof and disposed in sideby side relation with adjacent tubes being welded together throughouttheir length, pump means for establishing a forced circulationtherethrough and a steam and water drum supported a substantial distancebelow the furnaces upper end, burner means at said location forinjecting fuel into said furnace, said burner means being mounted forpivotal movement about a generally horizontal axis, means controllablydirecting said burner means to vertically adjust the zone of combustionwithin the furnace to control within limits the temperature of the gasesleaving the furnace, a generally horizontal gas pass extending laterallyfrom said combustion gas exit and having steam heating heat exchangeelements disposed therein operatively connected to receive and heat thesteam generated in said circuit, a vertical gas pass extending upwardlyfrom the exit and of said horizontal gas pass to an elevationsubstantially below that of the upper end of the furnace and also havingheat exchange elements disposed therein including steam heating elementsoperatively connected to receive and heat steam generated in saidcircuit, a rotary regenerative air heater means disposed immediatelyover said horizontal gas pass and intermediate said vertical gas passand said furnace and located a substantial distance below the upper endof the furnace, said air heater being connected with the outlet of saidvertical gas pass to receive combustion gases therefrom and connectedwith said furnace to supply preheated air thereto, the length of saidhorizontal gas pass being such as to permit said airheater to becompactly positioned between said vertical gas pass and said furnace, asupport framework for supporting said boiler and disposed about saidfurnace, said framework terminating at a height adjacent said drum andsub stantially below the upper end of said furnace and being effectiveto directly support said drum, said support framework beinginterconnected with said boiler at said height and in a manner so thatthe furnace is suspended therefrom.

3. A steam generating installation of the controlled circulation typecomprising two parallel side by side slightly spaced upright furnacesfired in their upper region at a location spaced somewhat below theirroofs and having their sole exit for combustion gases adjacent theirlower end, each of' said furnaces being of rectangular transversesection and having longitudinally extending steam generating tubeslining their walls and roofs, a

6 common steam and water drum with which said tubes communicate andwhich is disposed a substantial distance below the furnaces upper end atapproximately the midpoint of the furnace, pump means communicating withsaid drum and said tubes and effective to force boiler water throughsaid tubes, burner means mounted in the vertical walls of each furnaceat said location for injecting fuel into said furnaces, said burnermeans being mounted for pivotal movement about a generally horizontalaxis, means controllably directing said burner means to verticallyadjust the zone of combustion within the furnaces to control withinlimits the temperature of the gases leaving the furnaces, a supportingframework disposed about said furnaces to a height above the center ofgravity thereof but substantially below the upper end thereof andinterconnected with the furnace thereat and in a manner so that thefurnace is suspended therefrom, means supporting said drum directly fromsaid support framework, two parallel generally horizontal gas passes oneextending from the exit of each furnace, two generally vertical parallelgas passes one extending upwardly from the exit end of each of thehorizontal gas passes to a height substantially below the top of thefurnace, heat exchange elements disposed in these gas passes operativeto receive and heat the steam generated in said steam generating tubes,a rotary regenerative air heater means positioned directly over one ofthe horizontal gas passes at an elevation substantially below the top ofthe furnace and communicating with the outlet of the vertical gas passassociated with said one horizontal gas pass, a second rotaryregenerative air heater means positioned directly over the otherhorizontal gas pass at an elevation substantially below the top of thefurnace and communicating with the outlet of the vertical gas pass, thelength of each horizontal gas pass being but slightly greater than thatof the horizontal dimension of the air heater means disposed thereabove,and a stack intermediate said air heaters and in communication therewithto receive combustion gases therefrom.

References Cited in the file of this patent UNITED STATES PATENTS1,860,364 LaMont May 31, 1932 2,003,419 Artsay June 4, 1935 2,312,375Whitney, Jr. Mar. 2, 1943 2,320,911 Cooper June 1, 1943 2,325,384 EmmetJuly 27, 1943 2,418,815 Baver Apr. 15, 1947 2,583,599 Schoessow Jan. 29,1952 2,697,420 Lloyd Dec. 21, I954 FOREIGN PATENTS 682,121 Great BritainNov. 5, 1952 693,029 Great Britain June 17, 1953

